Aggregation-Induced Emission-Active Hydrazide-Based Probe: Selective Sensing of Al³⁺, HF₂^–, and Nitro Explosives

Abstract

( E )- N ′-((2-Hydroxynaphthalen-1-yl)methylene)picolinohydrazide (H-PNAP) shows aggregation-induced emission (AIE) strictly in a 90% water/MeOH (v/v) mixture at 540 nm, and the solid-state emission is blue-shifted to 509 nm upon excitation at 400 nm. The AIE activity of H-PNAP is selectively quenched by 2,4,6-trinitrophenol (TNP) and 2,4-dinitrophenol (DNP) out of different nitroaromatic compounds with a limit of detection (LOD) of 7.79 × 10 –7 and 9.08 × 10 –7 M, respectively. The probe is nonemissive in aqueous medium (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid, HEPES buffer, pH 7.2); however, it shows a strong emission to Al 3+ (λ em , 490 nm) in the presence of 17 other biological metal ions, and the LOD is 2.09 nM which is far below the WHO recommended value (7.41 mM). The emission of the [Al(PNAP)(NO 3 ) 2 ] complex is quenched by HF 2 – (F – and PO 4 3– are weak quencher), and the LOD is as low as 15 nM. The probable mechanism of the sensing feature of the probe has been authenticated by 1 H nuclear magnetic resonance titration, mass spectrometry, Fourier transform infrared spectroscopy, Benesi–Hildebrand plot, and Job’s plot in each case. The probe has some practical applications such as recovery of Al 3+ from the drinking water sample, construction of the INHIBIT logic gate, and detection kits for Al 3+ and TNP/DNP by simple paper test strips. The probe, H-PNAP, has successfully been applied to the detection of intracellular Al 3+ and HF 2 – ions in the human breast cancer cell, MDA-MB-468.

A Fluorogenic Triphenyl‐Amine‐Naphthyl‐Hydrazide Probe Selective for Cu2+ and Cysteine Detection via an ON‐OFF‐ON Logic path with Real Applications

“…The plot shows linearity upto 20 μM and accounts the static quenching and on above 20 μM of [Cu 2+ ] it shows an upward bend along with inclusion of dynamic process. The constancy of lifetime of the excited state fluorophore even on addition of Cu 2+ further confirms the static quenching [53,54] …”

“…The constancy of lifetime of the excited state fluorophore even on addition of Cu 2 + further confirms the static quenching. [53,54]…”

Biphenyl-containing amido Schiff base derivative as a turn-on fluorescent chemosensor for Al3+ and Zn2+ ions

“…To date, several studies have reported the successful application of ''ON-OFF''-type fluorescent sensors based on Schiff base derivatives, containing fluorophore units for the detection of Al 3+ ion only. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] On the other hand, a significant amount of research works have also been done on the development of efficient Zn 2+ ion sensors. [27][28][29][30] Furthermore, single chemical sensors that detect both Al 3+ and Zn 2+ ions in the same solvents are still few in number.…”

Thiophene-Appended Benzothiazole Compounds for Ratiometric Detection of Copper and Cadmium Ions with Comparative Density Functional Theory Studies and Their Application in Real-Time Samples

“…Several compounds in the reported literature were considering just a single wavelength either quenched or enhanced. − To the best of the author’s knowledge, L2 is the first compound of its kind of simple conjugated thiophene-appended benzothiazole moiety for the ratiometric detection of metal ions. , Because ratiometric detection simultaneously measures the ratio of two emission bands, , it can exclude the distortion from the external environment and produce results that are more pronounced than intensity-based measurement.…”